Immunohistochemical demonstration of c-myc oncogene product in middle ear cholesteatoma.

Cholesteatoma epithelium is characterized by a dysregulation with a hyperproliferative growth and altered differentiation. In a variety of cells c-myc oncogene was found to be highly linked to the control of growth and differentiation. Expression of c-myc was studied in cholesteatoma epithelium using a monoclonal antibody directed against the 67 kDa c-myc protein product and the alkaline phosphatase-antialkaline phosphatase method. For quantitative analysis a computer-linked analyzing system was used. In contrast to normal skin, keratinocytes of basal and suprabasal layers showed nuclear staining in cholesteatoma epithelium. The extent of nuclear staining of epithelial cells in the cholesteatomas studied was significantly increased. Concurrent cytoplasmic staining was observed in both skin and cholesteatoma, but with a stronger reactivity in the latter. These findings suggest participation of the c-myc oncogene in cholesteatoma epithelium.